1. Field of the Invention
The present invention relates to a method and apparatus for mounting a large semiconductor chip, e.g., an Si-LSI, a GaAs-LSI, and a liquid crystal display (LCD).
2. Related Background Art
A flip chip is mounted by connecting all bumps provided to a semiconductor chip to pads on a board. For this purpose, a technique for maintaining the parallel degree between the semiconductor chip and the board is very important. A conventional technique for maintaining the parallel degree between the semiconductor chip and the board in this manner uses, e.g., an optical probe. According to this method, probe light beams are radiated on a semiconductor chip and a board, and light beams reflected by the semiconductor chip and the board are measured, thereby adjusting the parallel degree between them.
Recently, however, as the size of the semiconductor chip and board is increased, it has become difficult to maintain the parallel degree between a semiconductor chip and a board by the conventional adjusting method. This is supposed to be caused by the following two factors. First, according to the conventional method, although a deviation of parallel degree is detected from a deviation in angle, an error in this detecting method has become large. More specifically, even if a deviation in angle at a certain measurement point is very small, as the size of a semiconductor chip and board is increased, it appears as a very large deviation in angle at a location remote from the measurement point. Second, when the board is made of ceramic, a warp or undulation is present in the board due to the characteristics of a ceramic. As the size of the board is increased, these warp and undulation become unneglectable.
It is an object of the present invention to provide semiconductor chip mounting method and apparatus capable of sufficiently maintaining the parallel degree between a semiconductor chip and a board even when the size of the semiconductor chip and board is increased, thereby maintaining a high mounting yield.